1. Field of the Invention
The present invention relates to a watercraft.
2. Description of the Related Art
Regarding watercrafts, there is a maximum speed limiting control that limits a maximum speed of the watercraft. For example, the watercraft disclosed in U.S. Pat. No. 7,315,779 includes an ECU and a watercraft speed sensor that detects a watercraft speed. The watercraft speed sensor detects an engine rotational speed. If the watercraft speed sensor detects that the watercraft speed is larger than a prescribed maximum watercraft speed, then the ECU controls a throttle valve actuator such that an opening degree of a throttle valve is decreased. In this way, the maximum speed is limited.
When a maximum speed limiting control is executed based on a detection value obtained with a watercraft speed sensor as explained above, the maximum speed limiting control is affected by the precision of the watercraft speed sensor. For example, U.S. Pat. No. 7,315,779 discloses using a pitot tube or a paddlewheel type sensor as the watercraft speed sensor. Since a pitot tube and a paddlewheel type sensor detect the watercraft speed using water flow, the accuracy with which the watercraft speed is detected can differ depending on the angle with which the water flow hits the pitot tube or the paddlewheel. In such a case, it is not easy to accurately determine whether to execute the maximum speed limiting control.
Therefore, it is possible to determine whether to execute the maximum speed limiting control based on the engine rotational speed instead of the watercraft speed. The engine rotational speed can be detected more accurately and easily than the watercraft speed. However, the engine rotational speed does not necessarily correspond to the watercraft speed and it is possible for a situation to occur in which the engine rotational speed is large but the watercraft is not even travelling on water. For example, even if the engine is operated with the watercraft on the ground, the maximum speed limiting control would be executed when the engine rotational speed exceeded a prescribed rotational speed threshold value.